Cao Cao (155 – 220 AD), with styled Meng De and alias Aman was born in Qiao County (today’s Bozhou, Anhui Province). He was a great strategist, statesman and poet in the Three Kingdom Period. He was entitled as the Emperor Wu of Wei after his son Cao Pi became the Emperor of the Wei Dynasty.
Cao Cao was born in an official aristocratic family. His father Cao Song is the descendant of Xia Hou, and afterwards became the adopted son of Cao Teng (a court official).
Cao Cao was both civilly and militarily outstanding when he was young. At that time, there was a man living in Runan named Xu Shao who was famed for his ability to evaluate one's potentials and talents. Cao Cao paid him a visit in hopes of receiving the evaluation that would earn him some political reputation. Originally, Xu pondered and refused to make a statement; however, under persistent questioning, he finally said, “You would be a capable minister in peaceful times and an unscrupulous hero in chaotic times.”
Cao Cao was a warlord and the penultimate Chancellor of the Eastern Han Dynasty who rose to great power during the dynasty's final years. As one of the central figures of the Three Kingdoms Period, he laid the foundations for what was to become the Wei Dynasty and was posthumously titled Emperor Wu of Wei. Cao Cao has also been praised as a brilliant ruler and military genius who treated his subordinates like his family. He was also skilled in poetry and martial arts and wrote many war journals.
Guandu Battle took place in 200 between Yuan Shao and Cao Cao. Yuan Shao amassed more than 100,000 troops and marched southwards on Xuchang in the name of rescuing the emperor. Cao Cao gathered 20,000 men in Guandu, a strategic point on the shore of the Yellow River. Despite his overwhelming advantage in terms of manpower, Yuan Shao was unable to make full use of his resources because of his indecisive leadership and Cao Cao’s location.
With the help of a defector from Yuan Shao’s army, Xu You, who informed Cao Cao of the location of Yuan Shao's supply depot, Cao broke the stalemate and sent a special task force to burn all the supplies of Yuan's army and won a decisive and seemingly impossible victory.
It was a famous battle in which the side with fewer men defeated the vast numbers of the opposition. Then Cao Cao easily defeated the Yuans taking good advantage of internal conflict in Yuan’s family. Henceforth Cao Cao took effective power over all of northern China. He sent armies further out and expanded his control across the Great Wall into its northern affiliate (today’s Korea), and southward to the Han River.